Since many recent works have extended the original Gran-CAM, we compare the results of different CAM methods, including XGrad-CAM [1]}, Grad-CAM++ [2]}, Eigen-CAM [3]}, Ablation-CAM [4]} and Score-CAM [5]}. In Table REF , we can see that almost all the CAM methods (except Eigen-CAM) can capture the characters' regions. However, in terms of the inference time, Grad-CAM is the fastest as it is the most straightforward method.
Therefore, we use Grad-CAM in our experiment for time-saving character region extraction.
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